Process for the production of transglutaminase-containing food having improved texture

ABSTRACT

PCT No. PCT/JP88/00657 Sec. 371 Date Feb. 3, 1989 Sec. 102(e) Date Feb. 3, 1989 PCT Filed Jun. 30, 1988 PCT Pub. No. WO89/00011 PCT Pub. Date Jan. 12, 1989.A process for the production of food having improved texture is disclosed wherein 0.001 to 5 parts by weight of transglutaminase is added to 100 parts by weight of a food material containing one or more materials selected from the group consisting of fish meat, animal meat and fowl.

TECHNICAL FIELD

This invention relates to a process for the production of food. Moreparticularly, it relates to a process for the production of food havingimproved texture and properties or peculiar texture and properties whichconsists of adding transglutaminase to a food material containing fishmeat, animal meat and, fowl, soybean protein, egg albumen or casein tothereby modify proteins contained therein.

BACKGROUND ART

Known methods for improving the texture and properties of food includephysical ones such as heating, cooling, stirring or cutting a foodmaterial and chemical ones such as adding salt thereto or controllingthe pH value thereof by adding an alkaline or acidic material thereto.Food mainly consists of proteins, lipids, saccharides, fibers, vitaminsand inorganic matters and the texture, properties, color, taste, odorand nutritive value thereof can be varied by modifying these components.It is believed, in particular, that the texture and properties of foodclosely relate to proteins, lipids, saccharides and fibers containedtherein. Thus it has been attempted to improve the properties of food bymodifying these components.

Each of the known methods for improving the properties of food asdescribed above exerts an intense physical or chemical effect on thecomponents of food. Thus it would tend to damage, for example, thecolor, taste, odor or nutritive value of food. In addition, it restrictsthe process for the production or processing of food. Further thesemethods should be carried out under severe control, otherwise varioustroubles such as discoloration, an offensive taste, an offensive odor,the liberation of water or a decrease in the yield might occur.

Accordingly it is an object of the present invention to provide aprocess for the production of food whereby a food of improved textureand properties or peculiar texture and properties can be producedwithout being accompanied by any trouble as described above.

DISCLOSURE OF INVENTION

In order to achieve the above object, the present inventors haveconducted extended studies. As a result, they have found thattransglutaminase added to a food material containing specific proteins,such as fish meat, animal meat and fowl, soybean protein, egg albumen orcasein, would exert a specific effect exclusively on the proteinscontained in said food material and modify the same without affectingany component of the food material other than the proteins to therebyachieve the following improving effects (1) to (5) which arecharacteristic or in common depending on the proteins to be modified.

(1) When transglutaminase is added to a food material containing fishmeat, the water retentivity of the food material is enhanced and thetexture thereof becomes flexible and smooth.

(2) When transglutaminase is added to a food material containing animalmeat and fowl, the water retentivity of the food material is enhancedand the texture thereof becomes hard to masticate.

(3) When transglutaminase is added to a food material containing soybeanprotein, the water retentivity of the food material is enhanced and thetexture thereof becomes hard and smooth.

(4) When transglutaminase is added to a food material containing eggalbumen, the foaming stability of the egg albumen is improved and thetexture of the food material becomes smooth and soft.

(5) When transglutaminase is added to a food material containing casein,the viscosity of the food material is strengthened and the texturethereof becomes smooth.

The present invention, which has been completed based on this finding,provides a process for the production of food consisting of adding 0.001to 5 parts by weight of transglutaminase to 100 parts by weight of afood material containing one or more materials selected from among fishmeat, animal meat and fowl, soybean protein, egg albumen and casein.

Now the process for the production of food according to the presentinvention will be described in detail.

The food material to be modified by the transglutaminase in the presentinvention contains one or more materials selected from among fish meat,animal meat and fowl, soybean protein, egg albumen and casein. In theaddition of the transglutaminase, the food material may be in any formdepending on the type and the purpose of the use. Namely, the foodmaterial may be either mixed with other materials or not.

More particularly, examples of the food material containing fish meatinclude ground fish meat, minced fish meat, fillet and lyophilized fishmeat powder. Examples of the food material containing animal meat andfowl include various minced animal meat and fowl and block meat.Examples of the food material containing soybean protein include soybeanmilk and soybean powder. Examples of the food material containing eggalbumen include egg albumen as it is and processed egg such as dry eggalbumen or frozen egg albumen. Examples of the food material containingcasein include cow's milk, skim milk powder and casein powder.

Although it is preferable that the transglutaminase to be used in thepresent invention is a highly purified one, crude ones such as thoseobtained from bovine, equine or swine plasma or liver extract may beemployed therefor.

The transglutaminase may be added in an amount of 0.001 to 5 parts byweight in terms of the pure enzyme, preferably 0.01 to b 5 parts byweight, to 100 parts by weight of the food material. When the amount ofthe transglutaminase is smaller than 0.001 part by weight, only a smallamount of the transglutaminase would bind to the proteins in the foodmaterial, which results in only a limited effect. When it exceeds 5parts by weight, on the other hand, the effect is achieved within ashort period of time, which makes the processing of the food materialdifficult.

In the present invention, a calcium salt may be added together with thetransglutaminase to the food material, if required, to thereby furtherenhance the improving effect. Examples of the calcium salt includecalcium chloride, calcium carbonate, calcium sulfate and calciumphosphate.

It is preferable that the calcium salt is added in an amount of 0.001 to2 parts by weight, still preferably 0.005 to 0.1 part by weight, to 100parts by weight of the food material. When the amount of the calciumsalt is smaller than 0.001 part by weight, only a limited effect isachieved. When it exceeds 2 parts by weight, on the other hand, itimparts an undesirable taste to the food. When the food material alreadycontains 0.1 mM or more of calcium salt(s), the addition of any calciumsalt is unnecessary.

In carrying out the present invention, thus, the abovementionedtransglutaminase may be added to the abovementioned food material at aratio within the range as defined above at any stage of the productionor processing of the aimed food product. The food material containingthe transglutaminase may be processed in a conventional manner dependingon the purpose.

To further illustrate the present invention, the following Examples willbe given.

EXAMPLE 1

3 g of common salt was added to 100 g of ground Alaska pollack meat andthe resulting mixture was mixed with a small size high-speed cutter.Then 2 mg of a lyophilized transglutaminase powder was added thereto andthe mixing was further continued. The paste thus obtained was filled ina vinyl tube and heated to 30° C. for one hour and to 90° C. for 20minutes to thereby give a gel as the product of the present invention.For comparison, a control gel was produced in the same manner as the onedescribed above except that no transglutaminase was added.

The properties of the product of the present invention obtained aboveand those of the control one were determined with a rheometer. Table 1shows the jelly strength (JS), depression and whiteness of each product.

                  TABLE 1                                                         ______________________________________                                                       Product of                                                                            Control                                                               invention                                                                             product                                                ______________________________________                                        JS (g)           1260      1020                                               Depression (mm)  15.8      14.8                                               Whiteness        51.0      50.3                                               ______________________________________                                    

Table 1 suggests that the product of the invention is superior to thecontrol one in all of the JS, depression and whiteness. As the result ofan organoleptic test, the product of the invention was found to have ahigh water retentivity and a flexible texture, compared with the controlone.

EXAMPLE 2

2 mg of a transglutaminase powder and 50 mg of calcium chloride wereadded to 100 g of egg albumen. The obtained mixture was whipped with ahomogenizer and the foaming stability thereof was observed after 30minutes. Table 2 shows the results.

                  TABLE 2                                                         ______________________________________                                                   Product of    Control                                                         invention     product                                              ______________________________________                                        after 0 min  Fine and white  do                                                            foam                                                             after 60 min The foam hardly de-                                                                           The foam                                                      creased and was decreased                                                     still fine.     to 2/3.                                          ______________________________________                                    

Table 2 suggests that the product of the invention containingtransglutaminase is superior to the control one containing notransglutaminase in the foaming stability.

EXAMPLE 3

30 g of a lyophilized bovine plasma powder and 0.5 g of calcium chloridewere added to 1000 ml of cow's milk. The resulting mixture was stirredand then heated to 30° C. for one hour. The milk thus obtained wasprocessed in a conventional manner with the use of Bifidobacteriumbifidus to thereby give a yogurt. As the result of an organoleptic test,this yogurt was found to be extremely smooth and highly viscous and havean excellent texture, compared with conventional ones.

EXAMPLE 4

1000 ml of soybean milk was slowly heated to approximately 70° C. and 7g of calcium sulfate was added thereto under slow stirring. The obtainedmixture was maintained at 70° C. for five minutes and then slowly cooledto a material temperature of 35° to 40° C. Then 10 mg oftransgultaminase was added thereto and the resulting mixture was furtherslowly stirred. The proteinous suspension thus obtained was poured intoa mold and solidified therein to thereby give a tofu-like food. Theproduct thus obtained was hard and had a high water retentivity,compared with convnetional ones. It had a novel and smooth texture inthe mouth and favorable.

EXAMPLE 5

30 g of egg albumen, 30 g of common salt, 30 g of bovine plasma proteinand 1 g of calcium chloride were added to 1 kg of fine ground meat onshore SURIMI (2nd Grade) and thoroughly stirred. The resulting mixturewas treated in a conventional manner to thereby give a heated gel as theproduct of the present invention. For comparison, a control product wasproduced in the same manner as the one described above except that nobovine plasma protein was added.

The properties of the product of the present invention obtained aboveand those of the control one were determined with a rheometer. Table 3shows the JS, depression and whiteness of each product.

                  TABLE 3                                                         ______________________________________                                                       Product of                                                                            Control                                                               invention                                                                             product                                                ______________________________________                                        JS (g)           630       420                                                Depression (mm)  12.5      11.0                                               Whiteness        39.5      38.7                                               ______________________________________                                    

Table 3 suggests that the product of the present invention is superiorto the control one in all of the JS, depression and whiteness.

EXAMPLE 6

30 g of bovine plasma protein and 1 g of calcium chloride were added to100 g of egg albumen and the obtained mixture was foamed byhomogenizing. Separately, 30 g of common salt and 500 g of water wereadded to 1 kg of fine ground meat on shore SURIMI (2nd Grade) andthoroughly stirred. Then the obtained mixture was mixed with the foamedegg albumen prepared above and molded. The molded product was heated to90° C. for 20 minutes. The foamed ground fish meat gel thus obtained hadan extremely smooth and soft texture.

EXAMPLE 7

700 g of salted minced lean pork, 300 g of lard, 250 g of water, 1 g ofa phosphate, 1 g of calcium chloride and 30 g of a bovine plasma powderwere mixed and stirred together. The obtained mixture was filled in acasing and smoked at 40° C. for 90 minutes and heated to 70° C. for 60minutes to thereby give a sausage as the product of the presentinvention. For comparison, a control product was produced in the samemanner as the one described above except no bovine plasma powder wasadded. The product of the present invention was superior to the controlone in the resistance to the teeth and water retentivity, thus beingfavorable.

INDUSTRIAL APPLICABILITY

According to the process of the present invention, transglutaminaseexerts a specific effect exclusively on proteins contained in food andthus modify the properties of the food without affecting any othercomponent thereof. Thus the process of the present invention enablesproduction of food of improved texture and properties or peculiartexture and properties without damaging, for example, the color, taste,odor or nutritive value of the food.

We claim:
 1. A process for production of food having improved texturewhich consists of reacting 0.001 to 5 parts by weight oftransglutaminase to 100 parts by weight of a food material containingone or more materials selected from the group consisting of fish meat,animal meat and fowl.
 2. The process of claim 1 wherein 0.001 to 2 partsby weight of a calcium salt is further added to 100 parts by weight ofsaid food material.
 3. The process of claim 1 wherein said food materialfurther contains egg albumen.
 4. The process of claim 2 wherein saidfood material further contains egg albumen.
 5. The process of claim 4wherein said material is fish meat.
 6. The process of claim 4 whereinsaid material is animal meat.
 7. The process of claim 4 wherein saidmaterial is fowl.
 8. The process of claim 2 wherein said material isfish meat.
 9. The process of claim 2 wherein said material is animalmeat.
 10. The process of claim 2 wherein said material is fowl.
 11. Theprocess of claim 1 wherein said material is animal meat.
 12. The processof claim 1 wherein said material is fish meat.
 13. The process of claim1 wherein said material is fowl.